Cushions heretofore available have been made from a great number of materials such as foams and gels. In particular, stable elastomeric block polymer gels ""such as those described in U.S. Pat. No. 3,676,387 have been utilized which are polymer-oil combinations. Elastomeric block polymers have been combined with oils in order to control the flexibility and compressibilities of the gels. For example, when an elastomer block polymer, such as described in the hereinabove referenced U.S. Pat. No. 3,676,387, is combined with a non-aromatic paraffinic oil low volatility, an extremely highly elastic material can be obtained. This gel is thermoplastic/thermosetting and is capable of being melted upon heating for casting in the formation of molded or other articles at room temperature.
Unfortunately, these gels, after formation, tend to exude oil over long periods of time. Accordingly, in order to utilize these gels in an acceptable cushion, they must be encapsulated or covered with a material to prevent-seepage of oil therefrom, which can cause staining to any support used for the cushion or provide an uncomfortable oily-like surface if in direct contact with a user.
Accordingly, such gels have been bonded to fabrics and films in order to encapsulate the gels. The bonding or lamination of the gel is typically done at high temperatures, for example, about 400xc2x0 F., and when used with very thin films, such heated contact can cause shriveling, or bubbling of the film, which results in an unattractive finished product. The use of very thin films is very important in the overall suitability of the cushion in order to prevent restriction of the flexibility and compressibility of the elastomer gel.
That is, uninhibited elastomer gel properties of flexibility and compressibility are desired in the final product. Heretofore, films utilized to encapsulate the elastomer gels require sufficient thickness to prevent the hereinabove noted stretching and bubbling of the film upon formation of the cushion. Unfortunately, such thick films inhibit the flexural and compressible characteristics of the gel which reduces the flexural and compressibility characteristics of the completed cushion.
The present invention is directed to an elastomer film laminated cushion which maintains the properties of the elastomer gel utilized, while at the same time providing a barrier for oil seepage from the elastomer gel into the environment.
An elastomer film laminated cushion in accordance with the present invention generally includes an elastomer having the physical properties of flexibility and compressibility in the range of flexibilities and compressibilities of stable elastomer block polymer gels. The film provides a means for encapsulating the elastomer with the film having the physical properties of flexibility to enable uninhibited flexure and compression of the elastomer by a user.
Importantly, a compatibilizing layer provides a means for laminating the film to an exterior of the elastomer. More particularly, the compatibilizing means enables the heat lamination of the elastomer to the film at temperatures up to about 400xc2x0 F. without shriveling and/or bubbling of the film. Also, the compatibilizing layer means has physical properties of flexibility to enable uninhibited flexure and compression of the elastomer by a user.
The physical properties of both the film and the compatibilizing layer are important in order to enable the cushion to provide desirable flexibility and compressibility of the elastomer, while at the same time preventing any oil leakage from the cushion.
More particularly, when the film is formed from a urethane resin and the elastomer is formed from elastomer resin, the compatibilizing layer means comprises a mixture of the urethane resin and the elastomer resin or a compatible elastomer resin.
In order to provide desired physical properties of the film and the compatibilizing layer, the film should have a thickness of between about 1 mil and about 5 mils and the compatibilizing layer should have a thickness of between about 10 mils and about 15 mils. With these thicknesses, the flexibility and compressibility properties of the gel are uninhibited and thus the physical properties of the resulting cushion are substantially the same as those of the elastomer.
Still more particularly, the compatibilizing layer mixture may comprise about 25 percent urethane resin and about 75 percent elastomer resin.
A method in accordance with the present invention for producing an elastomer film laminated cushion generally includes the steps of providing a thermosetting elastomer resin and a urethane film.
A compatibilizing layer is applied on to the film with the compatibilizing layer comprising a mixture of urethane resin and additional elastomer resin.
The elastomer resin is heated to form a gel and thereafter laminated to the compatibilizing layer at temperatures of up to about 400xc2x0. A gel forms an elastomeric body having physical properties of flexibility and compressibilities in the range of flexibilities and compressibilities of stable elastomer block polymer gels.